# A student connects an ammeter and a voltmeter to measure the current through a resistor and the potential difference across it. State where each instrument must be connected in the circuit and explain why each must be connected in that position.

> Cambridge International IGCSE Physics (0625) — 4.3 Electric circuits · State and Explain · 4 marks

## Mark scheme (4 marks)

1. The ammeter must be connected in series with the resistor.
2. So that the same current that flows through the resistor also flows through the ammeter / to measure the current passing through the resistor.
3. The voltmeter must be connected in parallel with (across) the resistor.
4. So that it measures the potential difference (work done per unit charge) across the resistor / so both terminals of the voltmeter are at the same points as either end of the resistor.

## Key terms

- [ammeter](https://www.gradenine.co.uk/glossary/ammeter)
- [voltmeter](https://www.gradenine.co.uk/glossary/voltmeter)
- [potential difference](https://www.gradenine.co.uk/glossary/potential-difference)
- [current](https://www.gradenine.co.uk/glossary/current)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
- [How to answer "State and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-connects-an-ammeter-and-767ba737) · Published by Druglandscape Ltd.